Expansion drill or cutter



(No Model.)

S. W. DOUGLASS.

EXPANSION DRILL 0R CUTTER.

No. 392,592. Patented Nov. 13, 1888...

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SAMUEL W'. DOUGLASS, OF FORT COLLINS, COLORADO, ASSIGNOR TO THE M. O. BULLOCK MANUFACTURING COMPANY, OF CHICAGO, ILLINOIS.

EXPANSICN DRILL OR CUTTER.

SPECIFICATION forming part of Letters Patent No. 392.592, dated November 13, 1888.

Application filed February 6, 1888. Serial No. 263.160. (No model.)

To aZZ whom it may concern;

Be it known that I, SAMUEL W. Donennss, of Fort Collins, in the county of Larimer and State of Colorado, have invented certain new and useful Improvements in Expansion Drills or Gutters; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, and to the letters of refer- IO ence marked thereon, which form a part of this specification.

This invention relates to a class of rotary expansion-drills, earth-angers, or cutting-tools intended principally for use in rock or earth I5 boring, either to enlarge a hole already bored or to cut off an inserted casingpipe at some point below the earth or rock surface.

The invention consists in the novel features of construction hereinafter described and claimed.

In the accompanying drawings, Figure 1 is a central longitudinal section of a device embodying my invention,consisting of a tubular cutter-stock, pivoted cutters, and a movable piston in the stock, and showing the expansion-cutters in side elevation and fully extended. Fig. 2 is a similar section of part of the tubular cutter-stock, showing the piston therein in fragmentary side elevation and the expansion-cutters in side elevation and retractcd. Fig. 3 is a transverse section of the drill-stock through the axis of 'the cutterblocks, but showing said cutter-blocks and their supporting-pivot in top view. Fig. 4 is a side view of one of the expansion-cutters of form suitable for earth boring, detached. Fig. 5 is a side view of one of the cutters detached and provided with diamonds for use in enlarging a hole in rock. Figs. 6 and 7 0 are respectively top views of the detached cutters shown in the side view in Figs. 4 and 5.

In the drawings, A is a strong tubular metal stock-say one foot (more or less) in length- 5 adapted to be secured at its upper end, by

screw-threads a or otherwise,to a rotary drillrod. (Not hereillustrated.) It willcommonly be adapted for such attachment at both ends, as shown, in order that it may be connected between two sections of drill-rod for its more perfect guidance by bearings within the hole or casing both above and below the cutters,

or that in its use for enlarging a hole it may be connected to a lower end cutter which will sink the hole of smaller size in advance of the expansion-cutters. In the upper part, a, of the tubular stock A, below its screw-threads or other portion connecting with the drill-rod,

is fitted a deep movable piston, B, the upper surface of which is exposed to the pressure of the water column within the drill-rod. Below the pistonspace a the stock or tube A is provided with two opposite longitudinal slots, a

a, through which the points of the cutters are to be protruded or retracted. 6 5

' G O are the cutterblades, consisting of metal blocks having flat contiguous faces and rotatably supported near their middle on a stout pivot, c, which is diametrical to the tube A, is about centrally opposite the slots a and is at right angles to the plane in which said slots are situated. The cutter-blocks G C have points or working ends 0, which, when the blocks are horizontal or extended, protrude through the opposite slots a the distance desired, but which may be retracted within the slots by a partial rotation of the cutter-blocks in that direction which carries the points downward. In the best construction the cutter-blocks at their opposite ends 0 extend into the adjacent slots, so that each of the two slots is occupied by the heel of one cutter and the point of the other, and each cutter-block is supported at both ends against the resistance of its work, thus avoiding the imposi- 8 tion of great strain upon the pivot 0. The flat under surface of the piston B bears on the upper surfaces of the cutter-blocks, preferably at both sides of a vertical plane passing through the axis. The upper rear corners of 0 the cutters are also rounded, as shown.

D D are coiled springs surrounding the pivot c, affording a frictional engagement of the two cutting-blocks O O, to press said blocks tightly together,so that when the cutters are retracted, 9 5 as illustrated in Fig. 2, by the withdrawal of the tool from the hole or casing, or otherwise, they will, by the friction of their surfaces upon each other, retain their retracted position and uphold the piston. The upper end of each :00 slot at has a narrow part or extension, 0?,

' which accommodates the heel of one of the cut ters, and against the upper end of which, as a stop, the heel of the cutter strikes in limitation of the retracting movement thereof produced by the spring D. The shoulder a of each slot at at the upper end of the broader part of the slot may similarly act as a stop to the extreme upward movement of the point of each cutter. The cutters, thus arranged and combined with the springs or their equivalent will normally stand in their retracted and inclined position and uphold the pistonB when not opposed by pressure from above. however, a water column or water under pressure is admitted above the piston, the latter,by bearing down upon the heel of the cutters G, will throw out their points against the rock or pipe-casing to be cut by them. As the cutting proceeds the piston will be more and more depressed and the cutters will approach their horizontal position. When this horizontal or extended position of the cutters is reached, they are held in such position, so that in the further operation of the drill, as in the downward enlargement of a hole, they will continue the cut downward to the full diameter which the extended cutters will make it. After merely severing a casing the cutter will be withdrawn as soon as the casing is cut through.

For the enlargement of a hole in clay or solid earth the form of cutters shown in Figs. 4c and 6 will commonly be used, for the enlargement of a hole in rock the form shown in Figs. 5 and 7, and for the severing of a casing the metal-cutting tools shown in Figs. 1 and 2 will be employed. The style of cutter is, however, not material to my invention.

For the purpose of supplying water to cutters when at work, one or more small holes, b,

may be provided through the piston, or the piston may be iii-ted loosely enough in the stock to give a suitable small passage of water to the cutters.

It is desirable to have some indication at the surface by which the operator may know when the cutters shall have become extended. For this purpose I propose, as a distinct improvement, to provide the piston with several laterally-discharging passages, I) b, and the tube with an annular enlargement, a communicating with said passages and giving a free and liberal ilow of water through the piston at the time the cutters are fully extended. By this means the pump used to force water into the drill-rod and to give pressure thereon during the expansion of the drill will, upon the coincidence of the free passages b with the re cess a suddenly show a lessened pressure or a higher speed, indicating to the operator that the drill is expanded.

As a convenient way of cutting the passages through the piston, a large central hole, I), may be drilled into it from the top; or the piston may be cast of cup shape, as shown in dotted lines of Fig. 1, and into the hole or recess thus provided the lateral holes are drilled.

Manifestly a single cutter, O, can be employed with only less advantage than two, and

When,

for the general purposes of my invention the heel of the cutter need not protrude into a slot opposite that for the emergence .of the point. I do not wish,therefore,to be restricted in certain of the following claims to the employment of two cutters, nor to the projection of the heel of the cutter into engagement with the tube or stock.

The cutter-block may have a bearing only at itsheel or rear end upon the piston, and may strike the stop a without coming to a bearing against the piston on that side of the pivot-axis nearest the cutter-point,and in that case pressure on and through the piston will hold the cutter extended with only greater strain upon the pivot than when the cutter is so held by the piston alone by extended hearing at both sides of the pivot c. This construction is indicated in the dotted lines of Fig. 1, and is to be regarded as the equivalent of that shown in full lines of the same figure and covered by the following claims. Other arrangements of stops for limiting the movements of the cutter-blocks may be employed without departure from my invention.

Water has been spoken of as the medium of pressure upon the piston B, because that is the medium employed in earth and rock boring; but such pressure may be imparted through the medium of air or other substance, or under some circumstances through a rod or other weight or similar medium of pressure.

I am aware that cutters or cutter-bearing levers pivoted between their ends have been arranged in a tube in a substantially-vertical direction, the upper ends of the levers being drawn together or toward each other laterally to expand the cutters at their lower ends by means of a hollow cone embracing the upper end of the cutter-levers and externally screw-threaded to lit a surrounding fixed nut or cylinder. This is not my invention.

I claim as my invention- 1. The combination, in an expansion rock or earth drill, of a hollow stock provided with a lateral opening, a cutter-block supported between its ends upon a pivot fixed in the stock, said cutter-block being arranged within and across the stock in a substantially-horizontal position when extended, and a movable piston within the stock above and bearing upon the cutter-block, so as to depress the heel of the cutter=block and to thus force the cutting point thereof outward through the lateral opening in the stock.

2. The combination, in an expansion-drill, of a hollow stock provided with opposite lateral openings, two cutter-blocks supported between their ends upon a transverse pivot fixed in the stock, said cutter-blocks being arranged side by side within the stock and extended crosswise of the interior of the latter in a substantially-horizontal position when extended, a movable piston above the cutter blocks within the stock, and a spring or springs arranged to bear laterally against said cutterblocks.

I? If 3. The combination, with a tubular drillstock provided with two opposite lateral longitudinal slots, of two cutter-blocks supported centrally on a fixed transverse pivot side by side within the stock and extending crosswise thereof, each into both opposite slots, springs arranged to hold the cutter-blocks in inclined positions when their points are retracted within the slots, and a piston above the cutterblocks which bears upon the heels of said blocks and by pressure thereon forces them from their inclined to less inclined or horizontal positions for the protrusion of the cutterpoints.

4. The combination, with a hollow drill-stock having atits end a screw-thread or its equivalent for the attachment of the stock to a hollow drill-rod, and provided with one or more lateral openings, of one or more cutter-blocks movable inward and outward through said opening or openings by downward pressure upon theirinner ends, and a piston within the stock above the cutter block or blocks and detached both from the latter and from the drillrod, but in bearing upon the cutter block or blocks, whereby the piston, when subject to waterpressure from above, will protrude the cutter or cutters from the stock.

5. The combination of a hollow drill-stock having at its upper end a screw-thread or its equivalent for the attachment of the stock to a hollow drill-rod, and provided with one or more lateral openings, one or more cutterblocks centrally supported within the stock on a fixed pivot and arranged to protrude at one end from the stock when depressed at its opposite end, and a detached freely-movable piston within the stock above the cutter-blocks, bearing upon and depressing the heels of the latter by water-pressure from above the piston, said piston being provided with one or more passages, b, which supply water to the cutters in all positions of the piston.

6. The combination,with a hollow drill-stock provided with a lateral slot or opening, and with an annular interior recess, (4 of a centrally-pivoted cutter-block, the working end of which moves upwardly and outwardly through the slot, and a piston within the stock above the cutter-block subject to water-press ure for the protrusion of the latter, said piston being provided with a passage for water which communicates with the recess a only when the cutter is extended.

7. The combination,withahollowdrill-stock, A, provided with opposite slots a crossed cutter-blocks O, mounted side by side on a single central pivot, c, and each having its cutter or cutters at one end thereof, a spring or springs, D, arranged to give frictional engage ment of the cutter-blocks with each other, a piston movable within the stock above the cutter-blocks in bearing upon the rear ends of the latter, and suitable stops for limiting the rotation of the cutter-blocks.

In testimony that I claim the foregoing as my invention I'afiix my signature in presence of two witnesses.

SAMUEL XV. DOUG BASS.

Witnesses:

M. E. DAYTON, C. O. PooLE. 

